That’s the question the burgeoning marijuana industry has for the federal government. Tax law bars the businesses from deducting expenses related to the distribution of their product — even if they’re operating legally under state law.

Pot shops are banned from writing off labor, rent, health insurance, advertising costs or other expenses that most companies deduct to lower their tax bills. The result is a tax rate as high as 80 percent, according to the industry, for those in the 20 states with legal medical marijuana and the two states with recreational pot.

The situation has become a buzz kill for businesses where the marijuana industry is booming.

“The poor marijuana guys are treated more roughly in their tax situation than if they were involved in the sex trade,” said anti-tax lobbyist Grover Norquist, who backs a long-shot effort to change the law. Prostitutes and criminals who earn money illegally can write off expenses under Internal Revenue Service rules — but not pot sellers, according to tax experts.

While the Obama administration’s Justice Department has tacitly approved state legalization by doing nothing to stop it, the tax issue most likely requires a legislative fix.

The Justice Department last week said it would allow banks to work with pot companies, but it hasn’t shown interest in solving the tax issue. The IRS has told lawmakers it has no power to unilaterally act.

Meanwhile, Capitol Hill is showing little to no interest in the issue.

“Why would we allow companies operating in violation of federal law to take federal tax breaks? It makes no sense,” said Rep. Tim Griffin (R-Ark.), who sits on the House Ways and Means Committee, which handles tax policy.

Congress wrote section 280E into the Tax Code in 1982 after a drug dealer claimed his yacht and weapons as business expenses and a court essentially agreed. The law bars any company trafficking in illegal substances on a Justice Department drug list from taking tax credits and deductions.

Rogers called it the “most talked about issue” among grass retailers right now.

“It would be nice to be treated like a normal citizen, but we’re working on it,” said Elliott Klug, the CEO of dispensary chain Pink House Blooms.

Klug — whose Colorado-based business started as a medical dispensary chain and is in the process of applying for recreational licenses — said the marijuana industry suffers from tax expenses that no other industry in the United States faces.

Some medical dispensaries have tried to work around the law, creating elaborate side businesses like acupuncture, alternative medicine or other patient services in hopes of being able to deduct some costs.

Harborside Health Center, which bills itself as the largest pot dispensary in the world, is one of many marijuana businesses involved in a protracted legal fight over deductions with the IRS.

Many cases are winding their way through tax court — but, in the interim, business owners and dispensary operators are left guessing about how to file their tax returns.

In tax filings dating back to 2009, Harborside — a nonprofit that also operates as a holistic care clinic — claimed that only about 5 percent of its employees’ time was spent on the actual retail sale of marijuana. It attempted to deduct 95 percent of its operating expenses, which included employing an addiction counselor, offering yoga and running food-collection programs, for example.

The IRS rejected the claim and slapped it with “a $2.5 million back-tax bill for the first two years,” said Steve DeAngelo, Harborside’s co-founder and executive director.

Lawmakers, particularly Republicans, seem puzzled when questioned about the situation, with exasperated looks that say: Did you really just ask me about tax breaks for pot?

Ways and Means Republican Rep. Kenny Marchant of Texas, who opposes both recreational and medical pot use, said he has “never heard any discussion about it.”

Tax panel Democrat Rep. Xavier Becerra of California, a state with a huge medical marijuana industry, said he “never thought of it.”

A bipartisan bill sponsored by Rep. Earl Blumenauer (D-Ore.), which would add a line in the Tax Code that allows pot companies in legalized states to write off business expenses, has just 12 co-sponsors. His office estimates the federal income tax rates for pot companies average between 65 percent to 75 percent.

Rep. Jared Polis (D-Colo.), one co-sponsor, said the deductibility quagmire could throw the whole legalization effort into jeopardy and send people back underground.

“When you remove deductibility, it can drive up the cost of the product. And for the entire legalization concept to work, the prices have to be below or at the black-market prices.”

The National Cannabis Industry Association, a trade group, is trying to rev up support for Blumenauer’s bill, recently hiring its first full-time lobbyist, Michael Correia — a former staffer to former Rep. George Radanovich (R-Calif.) and the House Natural Resources Committee.

Correia plans to approach Ways and Means members about Blumenauer’s bill first, then move to lawmakers from states with legalized medical marijuana. Harborside’s DeAngelo helped organize a separate coalition of like-minded groups called 280E Reform.

NCIA is framing the issue not as a weed legalization issue — which would never pass a GOP-controlled House — but a “tax fairness” issue that could appeal to Republicans.

Norquist argued that Republicans should support the bill for their love of state autonomy: “Go to a conservative and make the case that this is about federalism,” the Americans for Tax Reform president said.

But skeptics said the reality is that pot still is an illegal substance under federal law.

“These companies should take their money and run, given the fact that their profits are illegal in the first place,” said Kevin Sabet, a former senior adviser at the White House Office of National Drug Control Policy in the Obama administration and founder of the group Smart Approaches to Marijuana.

Rep. Dave Reichert (R-Wash.) said he would be “open-minded” to letting medical-only pot shops take tax deductions. The former policeman’s mother used medicinal marijuana to numb her pain before she passed away from cancer.

“It’d have to be very, very narrowly written,” so recreational-use businesses couldn’t take advantage, he said.

Most Republicans want to avoid the issue entirely. Ways and Means Chairman Dave Camp (R-Mich.) wouldn’t take a position when asked about it.

“The GOP won’t want to have this conversation until they have to, and 20 states with legalized medical marijuana use isn’t going to force it yet,” said a GOP staffer who works on tax issues.

Even Dana Rohrabacher of California, a Republican co-sponsor of the bill, said it “has very little chance of passage” at this time, because it could be seen as pro-weed.